When do you tell your employees?

Claudia
8w3d here. I'm a middle manager. I've already told my boss I'm pregnant but I haven't told my team, consisting of two employees. I don't like feeling like I'm being deceptive and I want to explain why I'm not as sharp as usual but I just don't know if I'm ready to share the news. I mean, if I were to miscarry, I would probably take a few days off to recover (emotionally and physically) and I would tell my employees the reason for it, so I'm not totally sure what's holding me back. 
I suppose it's the thought that every person I tell leads to a bigger chance of other people finding out and I don't plan to tell my other colleagues until well into January. It's not that I don't trust them, but people talk and then something accidentally slips and suddenly everyone knows.
Anyway, for those of you who are close to your boss, or who work on a small team, would you feel upset if you didn't learn of your boss or colleague's pregnancy until after the first trimester?